Computer Capabilities and LImitationsCapabilities1. Ability to Perform Certain Logic Operations2. Ability to Provide New Time Dimensions3. Ability to Store and Retrieve Information4. Ability To Control Error5. Ability to Check Itself

Evolution of COMPUTERSKnowledge about the history / evolution of computers gives us a deeper understanding of the origin and the gradual Mechanical to Electro-mechanical to Electronic technological changes that have brought about the kind of computers we see today, and help us to predict how they will be in future.Computers are everywhere!Generation of ComputersThe Computer GenerationsClassification of ComputersIV. Classification of computers according to Age• Here computers are classified according to time of their development. In this classification computers are categorized based on technology, speed and storage capacity among other factors

a. First Generation Computers• The first electronic computers were produced in the 1940s. Since then radical changes have taken place.o They were big in terms of sizeo They generated a lot of heato They used punched card as their mode of input.o They had an operation speed of 40, 000 operation/secondo They only required experts to operate.o They used vacuum tubes as their principle logic element.

b. Second Generation Computers• This was in the 1950s.• The principle logic element was Transistors.• They were smaller in size compared to the First Generation computers• Their operation speed was 200, 000 operations per second.• Their internal memory was inform of magnetic core/ drum and stored data on magnetic tapes.

c. Third Generation Computers• This was between 1960s – 1970s• Numerous Transistors were concentrated on a small surface to form ICs that served as the computer’s principle logic element.• Their processing speed was higher, 1, 000, 000 operations / second.• They were smaller than the first and Second Generation Computers.• They were multitasking in nature.• They had higher internal storage.

d. Fourth Generation Computers• They are the computers in use today.• They are the smallest in size.• They have higher processing speed.• They have large internal memory.• They are relatively cheap compared to others.

e. Fifth Generation Computers• They are many predictions that by the end of this century computers will have been developed which will be able to converse with people in a human like manner and which will be able to mimic human senses, manual skills and intelligence For example; Mobiles accept voice input/ output.

Dorothy D. ArominComputer DepartmentClassification of Computers According To TypeClassification of Computers According to SizeClassification of computers according to PurposeClassification of computers according to AgeThe origin of computing started with the early man who used fingers, stones, sticks, marks on walls, sand, etc. The word ‘compute’ was derived from two Latin words; ‘com’ which means ‘together’ and ‘putare’, which may means ‘add, calculate, count, or estimate’.TIMELINEA. ABACUS• Around 500 B.C. when the abacus was invented in Babylonia, then popularized in China.• The abacus helps people keep track of numbers as they do the computing. It is quick but has limited storage capabilities.• It is the first calculator or adding machine.• The abacus is still in use today by schools and shopkeepers in Asia. Blind children are taught to use the abacus to perform calculations.• The abacus is an excellent substitute for memorization of multiplication tables and teaching other base numbering systems, since it easily adapts itself to any base.

B. Napier’s Bones•John Napier, a Scottish mathematician, who became famous for his invention of logarithms in 1617. The use of “logs” made of bones enabled him to reduce any multiplication and division problem to a problem of addition and subtraction. The bones are a set of eleven rods with numbers marked on them in such a way that simply placing the rods side by side, products and quotients of large numbers can be obtained.Napier bones were multiplication tables written on strips of bones, ivory, silver, or wood. The invention was used for simplifying multiplication, division, and taking square roots and cube roots.It had a set of rods allowing computations up to 100,000,000.The left (or “index”) rod is fixed to the case. It is numbered from 1 to 9.The movable rods are numbered at the top.The numbers down them rods show the product of the number at the top times the corresponding number on the index rod.

C. Oughtred’s Slide Rule• With a common accuracy of only three digits, the slide rule an analog device, provided sufficient accuracy, but was not suited to situations where accuracy was needed such as in accounting.

• William Oughtred, English mathematician, invented the slide rule 1622. A slide rule consists of two movable rulers placed side by side. Each ruler is marked off in such a way that the actual distances from the beginning of the ruler are proportional to the logarithms of the numbers printed on the ruler. By sliding the rulers one can quickly multiply and divide.D. Pascal’s Mechanical Calculator• Blaise Pascal, French mathematician and philosopher, invented the Pascaline (1642 at the age of 18), the first mechanical adding machine.Pascalineo It is a gear-driven device, which makes a wheel turn one tenth of the way as the wheel to its right turns a full 360 degrees.o It could only perform addition and subtractiono Pascal built the Pascaline to help his father, a tax collector, calculate tax revenues.

E. Leibniz’s Mechanical Calculator (Leibniz’s Stepped Reckoner)• It was the first calculator that could perform all four arithmetic operations: addition, subtraction, multiplication and division.• Its complex gear work, however, was a bit beyond the manufacturing technology of the time;

• Mechanical problems, in addition to design defects in the carry mechanism, prevented the machines from working reliably.

F. Jacquard’s Loom• In 1801, Joseph-Marie Jacquard, of France made the first successful automatic draw looms by means of a series of instructions given to the threads by a punched card system.• The loom could produce complex patterns and pictures in silk and other materials.• By 1812, the punched card device was attached to 18,000 looms in Lyons.• The Jacquard loom was a technological break-through.• J.M. Jacquard even received a pension for his invention.

G. Babbage Analytical Engine

• He is therefore regarded as the “Father of Computers”.• His idea for the Analytical Engine consisted of 4 parts: an input device, a mill (processing unit), a storage device, and an output device.• It used punched-card system derived from the jacquard loom for input, processing and output.• Variable cards transported numbers back and forth from the mill.• It decided what operation to use, addition, subtraction, multiplication or division.• Babbage was a mathematician with a considerable interest in invention. He applied science to technology in a new and exciting way. Yet he never accomplished his goal and his machine was never built. The technology at that time is not appropriate to build his analytical engine because electronics was not yet developed and discovered.

The concepts of today’s computers (Input – Process – Output) was first visualized by Charles Babbage in 183 in England.H. Hollerith’s punched card tabulating machineLady Ada Augusta LovelaceA friend of Charles Babbage forwarded the idea about the use of punched cards to direct his engine to perform repeated instructions.She wrote down actual sequences of instructions for the machine.She invented and recognized programming concepts, such as the use of subroutines, looping and conditional jumps.Because of her work, she is generally regarded as the “world’s first programmer”. The programming language ADA, developed by the US Department of Defense, was named in her honor.

• In the 1890’s, Herman Hollerith, a statistician with the US Bureau of the Census, completed a set of machines to help process the results of 1890 census.• It was called Hollerith’s punched card tabulating machine.• Hollerith used Babbage’s idea of using punched cards for recording data. He then designed and built a sorting and tabulating machine that could work much faster than any human being. Unlike Babbage, Hollerith had the advantage of electricity in operating his machine.• Hollerith’s machine used a set of spring loaded wired suspended over the punched card reader.• When the wires were pressed onto the card, punched holes allowed wires to complete electric circuits. I. Punched Card Technology• Punched-card technology improved with the addition of more punched-card devices and more sophisticated capabilities, which eventually gave birth to the electromechanical accounting machines (EAM)• Among the EAM devices in use back then were the punched car, verifier, reproducer, calculator and the accounting machine.

J. Konrad Zuse’s Z3• In 1941, Konrad Zuse built the first programmable computer called the Z3. A computer is “programmable” because it is capable of following instructions.K. Atanasoff Berry Computer (ABC)L. Mark I• Dr. John v. Atanasoff, a professor of Iowa State University, had begun to think about a machine that could reduce the time it took for him and his physics students to make long, complicated mathematical calculations.• He made concepts as an electronic medium with vacuum tubes, the base 2 or binary numbering system, memory and logic circuits set the direction for the development of the modern computer.• In 1939, Dr. John V. Atanasoff and one of his graduate student Clifford E. Berry created a prototype of the Atanasoff Berry Computer (ABC)• The ABC is the world’s first automatic electronic digital computer. • IBM unveiled its first electromechanical computer in 1944. Called Mark I, the first electromechanical computer and the first stored-program computer. Howard Aiken, a Harvard University Professor, built it.• It is huge machine about 1200 cubic feet in size (about 1 refrigerator) and contained thousands of electromechanical relays or switching devices.• 8 feet tall, 51 feet long, 2 feet thick, weighed 5 tons, used about 750000 parts, 500 miles of wires, 3-5 seconds per calculation.

• Dr. Grace Murray Hopper was a lady in the US Navy Bureau of Ships, who worked with Howard Aiken from 1944 and used his machine for gunnery and ballistics calculation.• One day, the program she was

running gave incorrect results and, upon examination, a moth was found blocking one of the relays.• The bug was removed and the program performed to perfection. Since then, a program error in computer has been called a bug.• Debugging is a process of finding and correcting errors, in a computer program or piece of electronic hardware.

The first generation (1946 – 1958): Vacuum TubesHallmark:• The computers used vacuum tubes.• The vacuum tube was an extremely important step in the advancement of computers.• Its purpose was to act like an amplifier and a switch.• Without any moving parts, vacuum tubes could take very weak signals and make the signal stronger (amplify it)

Physical set-up:• Physically, first generation computers were very large. Machines with hundreds of thousands of vacuum tubes were built, taking up space of several floors in big buildings. They weighed about 30 tons.Technology• They used punched cards and paper tape for input.• They used magnetic drums for memory• They had memory size of approximately 2 kilobytes of RAM.• They used binary number system.• Speed was about 10,000 instruction per second.

Software• First generation computers used machine language, the lowest-level programming language understood by computers.The first generation...Setbacks:• They broke down frequently (required standby technicians)• Needed very many people to operate due to their huge size• High level of training was required before use• They produced a lot of heat and burned out• They consumed a lot of power• They produced a lot of noise• They had limited primary memory, and so they were very slow• They were very expensive to buy, setup and maintain. • They were not portable• Manual assembly of individual components into one functioning unit required.• Air conditioning required

Examples of First generation Computers.a. ENIAC – Electronic Numerical Integrator and Computer (1946) was the first electronic digital computer. It had over 18,000 vacuum tubes. b. EDVAC – Electronic Discrete Variable Automatic Computer (1947) was built for the US Army’s Ballistics Research Laboratoryc. The UNIVAC – (1951) UNIVersal Automatic Computer was the first general-purpose electronic digital computer designed for commercial use.

The second generation (1958 – 1964): TransistorsHallmark:• A transistor is a semiconductor device used to amplify and switch electronic signals. It is made of a solid piece of semiconductor material,• The invention of the transistor in the mid-50’s replaced the vacuum tube and paved the way for smaller and cheaper computers.

Physical set-up:• The computers reduced in size as compared to first generation computers, and could now fit in one room.• A typical second-generation computer contained 10,000 transistors hand soldered and connected by wires.

Technology• They still used punched cards for input and printouts for output• Memory size expanded to approximately 32 kilobytes• The computers increased in processing speed and reliability- Speed was about 30,000 instruction per second• Transistors consumed less power as compared to vacuum tubes. • Memory moved from a magnetic drum to magnetic core technology, in which Hard disk storage was now available

Software• Second generation computers used assembly and other high level programming languages such as FORTRAN ( FORmula TRANslator) which allowed programmers to specify instructions in words.ENIACEDVACUNIVACENIACENIACENIACThe Third generation (1965 – 19670): Integrated CircuitsHallmark:• Integrated Circuits. An integrated circuit (IC) was just a combination of thousands of transistors and tiny wires onto a small “chip” made of semi-conductor material such as silicon.Physical set-up:• The computers extremely reduced in size – thousand times smaller than discrete circuit. – It is because of fabrication of various circuit elements in a single chip.• As a result, the computer could now fit onto a desk and the monitor became the largest visible part of the computer.• For the first time, Electronic Computers became accessible to a mass audience because they became cheaper.

Technology• The third generation of computers saw the production of first microprocessors• The keyboards and monitors replaced punched cards for input and output.• Magnetic hard disks were developed for storage purposes• Memory size expanded to approximately 2 megabytes of RAM• The computers became more reliable because of elimination of soldered joints and need for fewer inter-connections• Speed increased to 5 million instructions per second• Integrated Circuits consumed a lower electric power.• The noise produced by the computers reduced drastically.

Software• Simple programming languages like BASIC were introduced• Multi-tasking was now possible (users interfaced with an operating system which could run different applications at the same time.)

Hallmark:The Fourth generation (1971 – to date): Microprocessors• Microprocessors are VLSI devices. Very-Large-Scale Integration (VLSI) is the process of creating integrated circuits by combining thousands of transistors into a single chip.• The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.• At the heart of all personal computers and most workstations sits a microprocessor.

Physical set-up:• The physical size of computers kept on reducing generation to generation.• With the development of micro-chips, what in the first generation filled an entire room could now fit in the palm of the hand.

Technology• Development of the mouse and handheld input devices. • More powerful, they could be linked together to form networks. • A vast variety of Storage memory media used such as Floppy disks (1971),Optical Compact Discs(1982), USB flash drive disks(2000), etc. • Memory size progressively expanded up to more than 8 Gigabytes of RAM.• The computers became very reliable. • Speeds over 100 million instructions per second. • Merging of Telecommunication and Computing Technology. • They don’t require air conditioning because they have inbuilt cooling mechanisms.• Development of Laptop and Palmtop computers which were portable and suitable for business.

Software• Operating systems based on the Graphical User Interface (GUI) like Microsoft Windows 1.0 (1985) were developed. • A wide variety of Graphical User interface operating systems and application software have been developed.

The Fifth generation (Today – to Future): Artificial Intelligence and RoboticsHallmark:• Artificial intelligence (AI) is the ability of machines to have human capabilities, such as the five senses (to See, hear, feel, taste, smell), plus, understanding, communication, reasoning, learning, learning from past experiences, planning, and problem solving. • In the future computers may even drive cars for us. • We also could see them in every imaginable place at home, like gates, that open up for us automatically

Physical set-up:• The physical size of computers in this generation can be customized to any shape of interest – be it as small as a pen or in the shape of a human being.Technology• Very powerful, like never before. • Unlimited expandable Storage Hard disk drives. • Working Memory size to expand to more than 20 Gigabytes of RAM • The computers to become 99% reliable to the extent that computers will carry out dangerous operations in Hospitals. • More networking containing millions of interconnected 4th Generation computers. • Molecular computers expected, Composed of millions of DNA (Deoxyribo Nucleic Acid ) strands in plastic tubes. o THERE IS A POWERFUL computer hidden inside humans beings. It's not the brain but it’s DNA.• Diligent Robots will be highly used in many areas such as factories where repetitive tasks are done.

Software• Fifth-generation programming languages • There will be a wide variety of computer Application programs designed to solve specific tasks in a user-friendly manner.

The second generation...Setbacks:• They produced less noise but their cost was still very expensive• High level of training was required before use.• Transistors gave much heat that could damage other components.• Commercial production was difficult and costly.• The computers could still run only one application program at a time (Multi-tasking was not possible)• Air-conditioning was required• Manual Assembly of individual components into a functioning unit was required.

Examples of Second generation Computers.a. IBM 305 RAMAC – (1956) Was the first commercial computer that used a moving head hard disk drive (magnetic disk storage) for secondary storage. RAMAC stood for “Random Access Method of Accounting and Control”.b. The IBM 1401 – was a variable wordlength decimal computer that was announced by IBM on October 5, 1959c. The CDC 6600 – was a mainframe computer from Control Data Corporation, first delivered in 1964. It remained the world’s fastest computer from 1964 – 1965.

IBM 305 RAMAC IBM 1401 CDC 6600 The third generation...Setbacks:• Highly sophisticated technology required for the manufacturer of IC chips.• They required Air-conditioning in many cases due to the heat produced.• If any component in an IC fails, the whole IC has to be replaced a new one.• Operations at low voltages as ICs function at fairly low voltage.• Quite delicate in handling as these cannot withstand rough handling or excessive heat.

Examples of Third generation Computers.a. The PDP 8 – was the first commercially successful minicomputer. It sold more thatn 50,000 systems for $18,000.b. The HP-2115 – which was made by Hewlett-Packard (HP)c. Fast minicomputers such as IBM 360 series and ICL 19000 series

• Another very good development that came up in this generation (1969) was the Advanced Research Projects Agency Network (ARPANET), the world’s first operational packet switching network.• The ARPANET is the core network of a set that came to become the global internet.• The network was created by a small research team at the United States Department of Defense.

PDP 8HP-2115 IBM 360 The fourth generation...Setbacks:• Highly sophisticated technology required for the manufacture of VLSI chips. • In a microprocessor chip, the various components are part of a small semi-conductor chip and the individual component or components cannot be removed or replaced, therefore, if any component in a microprocessor fails, the whole microprocessor has to be replaced by the new one. • Operations at low voltage as microprocessors function at fairly low voltage. • Quite delicate in handling as these cannot withstand rough handling or excessive heat

Examples of Fourth generation Computers.a. The Xerox Alto (1973) was an early personal computer developed at Xerox PARC in 1973. It was the first computer to use the desktop metaphor and graphical user interface (GUI). b. The IBM 5100, the first commercially available portable computer, appeared in September 1975. c. The Apple Macintosh (1984 ), was a mouse-driven computer with a graphic user interface at a much cheaper price of $2,500.

Xerox Alto IBM 5100Apple Macintosh The fifth generation...Setbacks:• Highly sophisticated technology required for developing artificially intelligent computers and robots. • Obsession with computers is seriously spoiling the writing and thinking abilities of human beings because the computers will be the ones thinking for people.• Robotics in the fifth generation will cause unemployment as machines take on the jobs people could do, • There are many dangers that are to come with the sophisticated technology.

TOPIO (2007) Hospital Robots Vacuum TubeTransistorsIntegrated CircuitsMicroprocessorArtificial Intelligence and RoboticsI. Classification Of Computers According To Typea. Analog Computers• Analogue computers are types of computers measure physical quantity such as Temperature, pressure etc. Such Data is also known as continuous data or non-discrete data.• These computers are used for scientific and engineering purposes. They are not used for commercial data processing. Examples of analog computers include:• Speedometer of a vehicle• Thermometer• Barometer• Voltmeter etc

b. Digital Computers• Digital computers are types of computers are used for commercial work. They process data in terms of letters, values and even symbols this gives them their title (digital meaning they process data in digit form). • They function by taking discrete numbers and performing mathematical operations or calculations on them.

c. Hybrid Computers• Hybrid computers are types of computers whose data processing feature is a combination both for analog and digital. This is where the Analogous state of data is equated to digital form.• For example, in electronic fuel Transactions- a customer punches the worth of fuel he/she would like to purchase then the pump would release fuel equivalent to the amount punched by the customer.

II.Classification of Computers According to Size• When computers are classified according to size the key determinant of their classification is occupancy of physical space. That is; how much physical space do they take up? In this classification computers are organized with reference to occupation of physical space.• In this category we have arranged the computers from the Biggest to the smallest.

a. Super Computers• Super computers are the most expensive computers ever to be created.They the largest in terms of size and processing powero They are the most expensive.o They are used in scientific applications like in NASAo They are bulky.o They are very fast when processing data.o They are Multi tasking in Nature

b. Mainframe Computers• They are relatively huge and bulky.• They are relatively fast compared to Super computers.• They are less expensive compared to Super computers.• They store data on magnetic media.• They are majorly used in airline reservation centers.

c. Mini Computers• They are the scaled down versions of the Mainframe computers.• They have multi-tasking capability.

d. Micro-Computers• These are the smallest computers.• They are the cheapest• They are majorly used at homes and training institutions.

III. Classification of computers according to Purpose• When computers are classified according to purpose this basically means that they are categorized as per the reason behind their creation. They are meant to carry out various tasks as per the intention of their developers.

a. Special Purpose Computers. These are types of computers that are designed for a particular job/ or task. They are specifically designed to solve problems of a restricted nature. For example the ones used in Air traffic control and Weapon Guidance system.

b. General Purpose Computers• These computers are designed to solve a wide variety of problems. Within the limitation imposed by their particular design capabilities, they can be adopted to perform particular tasks or solve problems by means of specially written programs.

Advantages and Disadvantages of ComputersData Processing The manipulation of data into a more useful form, it is the modern name for paperwork and involves the collecting, processing, and distributing of facts and figures to achieve a desired result. Data processing includes not only numerical calculations but also operations such as the classification of data and the transmission of data from one place to another.Categories of Data Processing1. Manual Data Processing2. Mechanical Data Processing3. Electrical Data Processing